Shoemaking method



Aug. 6, 1940. w,` p, FIELD v 2,210,753

sHoEMAxING METHOD Filed Jan. 19, 1937 z sheets-sheet 1 nun nuff' I770621Z@ Wauw new Patented Aug. 6, 1940 UNITED STATES PATENT OFFICE f psnoEMAKT'NG METHOD Walter Field, Brockton, Mass.

Application January 19, 1937, Serial No. 121,258 p a claims. (c1.12-142) f row of edge stitching, which, in addition to fas- Thisinvention relates to the manufacture of shoes and more particularly toan improved shoe and to a process for making the same.

The main object of my invention is the provision of a cheap shoe havingboth inside and outside the appearance of genuine Goodyear welt shoe andhaving the durability and Ywearing qualities of a shoe of thatcharacter, and the provision of a method for making the same.v p

Another object of my invention is the provision of a cheap shoe of thewelt type, which mayhave either a leather outer sole or one of rubbercomposition or similar material.

Another object of the invention is the provi- 1'. sion of a method bywhich a strong, erlicient and durable bond between the outer sole andthe shoe upper is secured by the vulcanization to the upper of a Yweltof vulcanizable material, lwhich is permanently attached to the outersole.

An additional object ofthe invention' is the provision of a simplemethod for making shoes which eliminates many of the steps heretoforeconsidered necessary in the making of welt sho-es Vand which materiallyshortensthe time consumed in the production of the shoesy and materiallyreduces the cost thereof.

Other objects of the invention will be more particularly set forth anddescribed hereinafter.

My invention contemplates a shoe and method of making the same, inwhichk the ,louter sole is permanently fastened to the upper byvulcanization thereto of a Welt, which is permanently attached to theouter sole. This. is accomplished by impregnating the roughened bottomedges of the upper with vulcanzable material, such as rubber latex,containing vulcanizingagents, and

by using a welt of vulcanizable material, such as rubber composition.These parts are then 'coated with a solution made up of one ormore'vulc'ani'z'- ation `accelerators. dissolved in solvents capable ofdissolvingthe said vulcanizable material, and, after a short interval oftime, the coated surfaces are pressed together under a heavy pressurewhich is maintained fora suiiicient time to permit lvulcanization totake place.

In this manner, a rm and lastingbond is secured between the welt and theupper, due to the fact that the vulcanization results in an integralbonding body ofvulcanized material which permeates and becomes anintegral part of both the attached portions, so that they cannot beseparated without rupturingione or the other of the erably, the weltisattached to the outer sole `by .a

teningthe two parts together, has the advantage of a Goodyear welt shoe.The Welt, however, may be attached to the outer sole in any suitablemanner, either by vulcanization by the same method pursued in attachingthe welt to the upper, or it may, in some cases, be attached by cement,where the welt and the outer sole are of materials such as rubbercomposition, which permit the use of cement.

In the embodiment of the invention described hereinafter, rubber isdesignated as the preferable vulcanizable material used for attaching anouter sole to a shoe upper by vulcanization. This requires, of course,that ythe vulcanization accelerators used be adapted for dissolvingrubber. It is to be understood, however, that my invention is not to belimited to the use of rubber AasA the vulcanizable material, since thereare other vulcanizable substances which may be used in 1p-lace ofrubber, and ,other solvents especially adapted for those vulcanizablematerials. In any event, however, the welt must, in such case, be

made 'of the same vulcanizable material that is used-for `impregnatingthe 'edges of the lastedl upper. :In the accompanying drawingsillustrating my invention, Figure 1 is a side elevation of la mans shoeconstructed in accordance therewith;

Fig. 2.is a bottom plan view on an enlarged scale of a lasted upper andinner sole having the .surplusmaterial trimmed off, with the edges: o-f

receiving lposition;

Fig. 6 is a cross-.sectional View of. the welted soler unitA showninFig. 4;

l Fig. 7 is a similar View shown inFig. 5; and 1 Fig; 8 is asideelevation of `a portion of the ofthe welted sole vunit Welt. i

.In the drawings, my invention is shown vas .exemplified in a mansOxford shoe of the welt type, but it is to be .understood that this ismerely for the purpose of illustration and that the invention -is alsoapplicable to thel manufacture of womens and childrens shoes, and,generally, to

kthe:1`nanufacture of all kinds of footwear coming Vunclerthe genericterm shoe As shown, the

shoe comprises an upper designated generally as I, an inner sole I2, anouter sole I4, and a heel I6. The upper, which may be made in anysuitable manner, is shown as comprising outer parts consisting of avpair of quarters I8, a vamp 20, and a tip 22, andinner parts include alining 24, a box toe 20, and a heel'counter 28. The outer sole I4 isprovided with a welt 30 fastened thereto.

In the method of making a shoe according to my invention, the shoe upperis first prepared in the usual manner by assembling and fastening thevarious parts thereof in their proper relations, after which the innersole I2 is tacked to the last and the prepared shoe upper I0 is fittedover the last ready for the pulling-over operation. The upper is thenlasted, and this may be done by any suitable McKay method of lasting,either full cement lasting, step-by-step nail lasting, or staplelasting. A combination of the cement and staple methods is preferred forthe lasting operation, and, in carrying this out, the bottom edges andthe margin of the outer face of the inner sole are coated with anysuitable cement, and the edges of the upper are then pulled over andadhesively fastened to the inner sole, and the sides of the upper arestaple-lasted with staples 34 to the inner sole by the Well-knownLittleway process. In the latter process, the staples are of lightconstruction and are clenched within the inner sole without goingthrough and appearing on its inner surface. Around the toe, thepulledover edges of the upper may be temporarily held in place to permitthe cement to set, by pull-over tacks inserted in the toe portion of thelast. The edges of the upper around the heel are preferably lasted bythe use of permanent tacks 36, but these edges may be lasted by adhesivealone if desired. After the cement has thoroughly dried or set, thepull-over tacks are withdrawn and the surplus material of the upper,including the box toe and lining around the toe portion of the last, istrimmed off to provide a smooth, flat surface, as shown in Figure 2. Theexposededges of the outer leather-parts of the shoe upper are thenscoured or roughened in preparation for vulcanizing the outer solethereto.

Mymethod also includes the preparation of an outer sole unit, comprisingan outer sole I4, which may be of leather, rubber composition, or othersuitable material, and a welt 30 of vulcanizable material permanentlyattached to the outer sole. In the preparation of this unit, the koutersole is died out of suitable material to the exact form and dimensionrequired by the last and is prepared in the usual way. The welt ispreferably made of molded rubber composition and may be made in variousforms, but, preferably, its outer edge portion, which is exposed in thefinished shoe, is of uniform thicknesswith parallel top and bottomfaces, and its inner edge portion is 'beveled on its top face, and thewidth of the beveled portion 32, although it may be varied to suitvarying conditions, must be sufficient to insure a strong and durablebond between that portion of the welt and the edges of the shoe upperwhen those parts are fastened together by vulcanization. The welt isapplied around the margin of the forepart of the sole from the heelbreast on one side to the heel breast on the other side, and ispermanently fastened to the outer sole by any suitable means, such asstitching 40.

It is important that the welt be sufficiently tough to holdthe'stitching by which it is fastened to the outer sole and that it beof sufficient hardness, approximately between and 92, in order to retainits form and shape permanently, and that it be susceptible to chemicalagents adapted to dissolve rubber and to further vulcanization. Althoughthe Welt may be made of various rubber compositions, yet I have foundthat a composition made according to the following formula gives mostexcellent results and produces a welt which fully answers the foregoingrequirements. This composition is made up of the following ingredientsand parts by weight:

Parts Crude rubber in smoked sheets 27 Automobile tire reclaim 24 Innertube reclaim 7 Mineral rubber compound 2 Carbon-X 9 Vulcanizationaccelerator (DPG) 1.7 Carbon black 25.5

R-Kadox 2 VGB'I 1% Sulphur 1.7

The mineral rubber compound is a natural deposit which is used as afiller and a substitute for rubber and is a commercial product wellknown under the name MRX; the Carbon-X imparts toughness to thecomposition and is a well-known commercial product; DPG is a trade namefor a well-known vulcanization accelerator used with sulphur for thatpurpose; R-Kadox is a zinc solution used for hardening and is likewisewell known under that name; VGB` is an anti-oxygen agent to retardoxidizing and is well known under said designation; and carbon black isused for imparting toughness and rigidity to the compound, and, at thesame time, produces its black appearance.

The welt is formed from the composition by molding and is vulcanziedunder heat and pressure for from ten to fifteen minutes, so that when itis taken out of the mold, it is not entirely cured but is still subjectto further Vulcanization.

In attaching the Welt to the outer sole, I prefer to use a single lineof welt stitching 40, which is located in the outer portion of the weltso as to be Visible in the finished shoe. The stitching 40 may be eitherof the well-known lock or chain forms. When the lock stitching is used,it may be left exposed on the outer face of the outer sole, or it maybelaid in a narrow channel cut in the outer face of the sole and coveredby a turned-back portion; but in the case of chain stitching, it ispreferable to form a channel in parts of cleaned liquid latex 40 to 50%rubber content.

part colloidal zinc oxide.

0.4 part colloidal sulphur, and

0.75 part of a solution consisting of 3 parts of casein (fat free) 6.2parts of sodium sulphide 0.08 part of sodium salicylate 14.72 parts ofdistilled water.

The viscosity of this liquid Yat 20 C.

(Englers method) is 1.5`

This Solutionshould be liberally applied to the roughened surfaces andbrushed in so that ,it

will penetrate the edges of the upper thoroughly.

c More than one coating may be applied, but each coating must be allowedto dry thoroughly before the next coating is applied. Normally, acoating will dry in about half an hour. This step of my process may becarried out some days in advance of the next step, since the material inthe impregnated edges of the upper is not affected by aging for a periodof two months or more.

After the edges of the upper have been thoroughly permeated with thelatex mixture and have dried, the next step in my process consists intreating those edges and the welt with a solution containing one or morevulcanization accelerators dissolved in solvents capable of dissolvingrubber. One solution which is adapted for this purpose comprises thefollowing:

1 part of rubber. 99 parts of trichlorethylene.

l part of an accelerator such as a powder made up of 10 parts ofordinary commercial piperidine l0 parts of dithiocarbamate l0 parts ofcarbon disulphide 50 parts of china clay.

This powder is similar in composition to what is sold on the marketunder the name Superac.

This solution is applied in any suitable manner to the impregnated edgesof the upper and to the beveled portion of the welt, which is previouslyroughened up to remove the hardened film due to molding and to exposethe softer interior. A sufficient amount of the solution should be usedto soften up the rubber in the edges of the upper and the welt to anappreciable depth and more than one coat may be applied if necessary.After being coated, the parts are allowed to stand for from five to tenminutes until the rubber contents have been partially dissolved andsoftened, after which the welted sole unit is applied to and spotted onthe lasted upper and the parts are subjected to a pressure of at leasteighty-live pounds to the square inch for a period of from twelve totwenty minutes.

The pressure is preferably applied by suitable mechanical means and ahigher pressure than that specified is of advantage. My experience hasbeen that the higher the pressure and the longer it is sustained withinreasonable limits, the stronger is the bond between the welt and theupper.

Under this pressure, the accelerators in the last solution penetratethroughout the rubber in the edge of the upper and the welt and startcold vulcanization which unites in one integral homogeneous body therubber content present in both parts and securely locks the welt to theupper.

After the shoe is released from the pressure, the heel portion of theouter sole is then nailed around the heel in the usual manner, afterwhich the heel may be applied thereto. The edges of the outer sole andwelt may then be trimmed and set, or, if preferred, this operation maybe performed before the welted sole unit is fastened to the shoe upper.After this, the shoe is subjected to such furthen finishing operationsas required.

In Figures 5 and 6 of the drawings, the shoe is shown as made with aller 42, but it may be made without a filler. Any suitable filler may beused, such as a thin, firm, felt filler, which I have found gives thebest results, and this filler isl preferably applied to the shoe upperdirectly after it is lasted.

My method can be used not only with uppers having leather outer parts,but also with uppers in which the outer parts are of canvas or otherfabrics or other material of a fibrous character capable of beingpermeated by a solution of vulcanizable material.

Some of the important advantages of my invention are that it eliminatesmany of the costly operations now involved in producing a genuineGoodyear welt shoe and simplifies the process to an amazing extent; thatit leliminates the rough inside of theMcKay made shoe, whether producedby lock stitching or other variations of the McKay system; and that itfurther eliminates the stiff midsole, which is characteristic of theMcKay welt and nailed shoes, and, consequently, results in producing amore flexible and resilient shoe than any produced by either of thesystems mentioned above. In short, my invention permits the productionof a shoe having 'the appearance, both inside and out, the durabilityand wearing qualities, and other advantages of high-grade Goodyear weltshoes at a production cost of cheap shoes.

One of the advantages in using a welt of rubber composition, or similarmoldable material, is that the exposed face of the welt may be providedwith transverse corrugations 44 more closely simulating the appearanceof a Goodyear welt, as shown in Figure 3, which corrugatons may beformed in the molding process, and, therefore, are permanent and are notaffected by Wear. The same indentations in a leather welt disappear withthe absorption of moisture by the leather, so that the welt in timebecomes comparatively smooth.

Another important advantage which flows from the use of my invention inshoes having rubber composition soles is that the soles may be made of acolor to harmonize with the color of the shoe upper. During the past fewyears, there has been a growing tendency in the shoe manufacturingindustry to produce shoes having uppers of all `shades of color. Thistendency, which has heretofore been largely confined to womens shoes, isnow spreading to mens shoes, and it not only includes uppers ofdifferent colors, but also combinations of different colors in the sameshoe. Attempts have heretofore been made tocarry out these color schemesin shoes having leather soles by painting the soles and the' welts, ifprovided with welts, or by coating them with a veneer. This has notproved satisfactory, however, because the paint or veneer soon wears offand disappears. Rubber composition, however, can be made in any color,and soles and welt of this material can be made to match exactly thecolor of the shoe upper, or can be made of a different color in harmonywith the color of the shoe upper, and the color of the sole and Welt ispermanent. The coloring of rubber composition is done in the mixing andmolding of that material, so that there is no appreciable increase inits cost, whereas, the coloring of a leather sole and a leather Weltinvolves additional operations which increase the cost of the shoe.

Another important advantage of a shoe constructed by my method is thatit is substantially waterproof, because the joint between the edges ofthe upper and the welt is closed by a body of vulcanized rubber, whichis integral with the edges of the upper and the welt, and, thereby,

effectually prevents the entrance of moisture.

Although I have described herein, as a part of my invention, theattachment of the Welt to shown in Figs. 5 and 7 of the drawings, and

Where in the claims the Welt and outsole are defined as attached one tothe other, this language is intended to cover such integral constructionof a sole unit having a Welt portion and an outsole portion.

It is to be understood that my invention is not to be limited to theprecise forms herein shown and described, since it may be embodied invarious other forms, all Within the scope of the following claims.

What I claim is:

1. A method of making shoes consisting in lasting an upper over themarginal edges oi an inner sole, roughening the lasted edges of saidupper and then impregnating them with a vulcanizable material containinga vulcanizing agent, attaching a partially vulcanized Welt ofvulcanizable material along the margin of an outer sole, said Welthaving an inner longitudinal beveled portion of substantial Widthequaling the Width of the lasted edges of said upper, coating saidimpregnated lasted edges of said upper and the beveled portion of saidwelt with a solution containing a vulcanization accelerator dissolved ina solvent capable of dissolving said Vulcanizable material of said Weltand said edges, and then placing said outer sole against said lastedupper and subjecting said parts While in tacky condition to a heavypressure continued for a sufficient time to vulcanize said Welt to saidlasted edges for fastening said outer sole to said upper.

2. The method of attaching to a lasted upper a Welt having an innerlongitudinal bevelled portion of vulcanizable material which methodconsists in roughening the lasted edges of the upper and thenimpregnating them with a Vulcanizable material containing a vulcanizingagent, coating said impregnated edges and the bevelled portion of thewelt with a solution containing a vulcanizing accelerator dissolved in asolvent capable of dissolving the vulcanizable material of the Welt andedges, positioning the bevelled portion of the Welt against the lastededges of the upper, and subjecting the parts While in a tacky conditionto a heavy pressure continued for a suicient time to vulcanize the Weltto the lasted edges of the upper.

WALTER P. FIELD.

